This is my understanding of these terms. Originally a "fake book" was a collection of songs, usually standards with charts of chord progressions in the most basic, bare bones presentation. Such a book was useful to musicians who received requests from the audience and had to improvise on the spot music they didn't know really well. In other words, they could fake their way reasonably well through the marterial. It was also useful to musicians who were sitting in with other musicians, even though the "sitter-in" was not familiar with their repetoire.

Then better "fake books" were developed by large publishing houses--better in that they were more complete, more detailed and possibly more accurate a representation of the standards they contained--hence the name "real book."

Today one can buy books that call themselves "fake" and books that call themselves "real". If you are in a store, such as Barnes and Noble which sells a variety of these books, look through a few to see the differences in the way each one may present the same song.

There are fake books for blues, jazz standards, and show tunes...whatever.

I have an interesting book called "How to Get the Most Out of a Fake Book." As fake books present a skeleton of a song, this book has advice on how to "flesh out" the chart to make the music come alive, so to speak, no matter what instrument you play.

The original "Real Book" was an illegal compilation of the chord progressions (where applicable) and heads for a couple hundred copyrighted tunes. It was always typeset and bound poorly, and many of the changes were just plain wrong (tunes as simple as "All the Things You Are" have some wrong chords, ferchrissake), yet from talking to some jazzer friends I have found that it was quite expensive. I believe it originated at Berklee, as some of the Pat Metheny tunes listed there are titled "Exercise No. [x]," dating from when he taught there and would give them as exercises to his students.

The newer, legal Real Books are often fairly detailed. I'd like to get the Sher ones at some point, although all three volumes would run me $120.